18 files changed, 402 insertions, 167 deletions

diff --git a/crates/paths/Cargo.toml b/crates/paths/Cargo.toml
new file mode 100644
index 000000000..646ee7fd5
--- /dev/null
+++ b/crates/paths/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "paths"
+version = "0.1.0"
+authors = ["rust-analyzer developers"]
+edition = "2018"
+
+[lib]
+doctest = false
diff --git a/crates/paths/src/lib.rs b/crates/paths/src/lib.rs
new file mode 100644
index 000000000..c7ce0c42f
--- /dev/null
+++ b/crates/paths/src/lib.rs
@@ -0,0 +1,123 @@
+//! Thin wrappers around `std::path`, distinguishing between absolute and
+//! relative paths.
+use std::{
+    convert::{TryFrom, TryInto},
+    ops,
+    path::{Component, Path, PathBuf},
+};
+
+#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
+pub struct AbsPathBuf(PathBuf);
+
+impl From<AbsPathBuf> for PathBuf {
+    fn from(AbsPathBuf(path_buf): AbsPathBuf) -> PathBuf {
+        path_buf
+    }
+}
+
+impl ops::Deref for AbsPathBuf {
+    type Target = AbsPath;
+    fn deref(&self) -> &AbsPath {
+        self.as_path()
+    }
+}
+
+impl AsRef<Path> for AbsPathBuf {
+    fn as_ref(&self) -> &Path {
+        self.0.as_path()
+    }
+}
+
+impl TryFrom<PathBuf> for AbsPathBuf {
+    type Error = PathBuf;
+    fn try_from(path_buf: PathBuf) -> Result<AbsPathBuf, PathBuf> {
+        if !path_buf.is_absolute() {
+            return Err(path_buf);
+        }
+        Ok(AbsPathBuf(path_buf))
+    }
+}
+
+impl TryFrom<&str> for AbsPathBuf {
+    type Error = PathBuf;
+    fn try_from(path: &str) -> Result<AbsPathBuf, PathBuf> {
+        AbsPathBuf::try_from(PathBuf::from(path))
+    }
+}
+
+impl AbsPathBuf {
+    pub fn as_path(&self) -> &AbsPath {
+        AbsPath::new_unchecked(self.0.as_path())
+    }
+    pub fn pop(&mut self) -> bool {
+        self.0.pop()
+    }
+}
+
+#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash)]
+#[repr(transparent)]
+pub struct AbsPath(Path);
+
+impl ops::Deref for AbsPath {
+    type Target = Path;
+    fn deref(&self) -> &Path {
+        &self.0
+    }
+}
+
+impl AsRef<Path> for AbsPath {
+    fn as_ref(&self) -> &Path {
+        &self.0
+    }
+}
+
+impl<'a> TryFrom<&'a Path> for &'a AbsPath {
+    type Error = &'a Path;
+    fn try_from(path: &'a Path) -> Result<&'a AbsPath, &'a Path> {
+        if !path.is_absolute() {
+            return Err(path);
+        }
+        Ok(AbsPath::new_unchecked(path))
+    }
+}
+
+impl AbsPath {
+    fn new_unchecked(path: &Path) -> &AbsPath {
+        unsafe { &*(path as *const Path as *const AbsPath) }
+    }
+
+    pub fn join(&self, path: impl AsRef<Path>) -> AbsPathBuf {
+        self.as_ref().join(path).try_into().unwrap()
+    }
+    pub fn normalize(&self) -> AbsPathBuf {
+        AbsPathBuf(normalize_path(&self.0))
+    }
+}
+
+// https://github.com/rust-lang/cargo/blob/79c769c3d7b4c2cf6a93781575b7f592ef974255/src/cargo/util/paths.rs#L60-L85
+fn normalize_path(path: &Path) -> PathBuf {
+    let mut components = path.components().peekable();
+    let mut ret = if let Some(c @ Component::Prefix(..)) = components.peek().cloned() {
+        components.next();
+        PathBuf::from(c.as_os_str())
+    } else {
+        PathBuf::new()
+    };
+
+    for component in components {
+        match component {
+            Component::Prefix(..) => unreachable!(),
+            Component::RootDir => {
+                ret.push(component.as_os_str());
+            }
+            Component::CurDir => {}
+            Component::ParentDir => {
+                ret.pop();
+            }
+            Component::Normal(c) => {
+                ret.push(c);
+            }
+        }
+    }
+    ret
+}
diff --git a/crates/ra_assists/src/ast_transform.rs b/crates/ra_assists/src/ast_transform.rs
index 3079a02a2..00fa95b6c 100644
--- a/crates/ra_assists/src/ast_transform.rs
+++ b/crates/ra_assists/src/ast_transform.rs
@@ -106,6 +106,7 @@ impl<'a> SubstituteTypeParams<'a> {
             _ => return None,
         };
         // FIXME: use `hir::Path::from_src` instead.
+        #[allow(deprecated)]
         let path = hir::Path::from_ast(path)?;
         let resolution = self.source_scope.resolve_hir_path(&path)?;
         match resolution {
@@ -150,6 +151,7 @@ impl<'a> QualifyPaths<'a> {
             return None;
         }
         // FIXME: use `hir::Path::from_src` instead.
+        #[allow(deprecated)]
         let hir_path = hir::Path::from_ast(p.clone());
         let resolution = self.source_scope.resolve_hir_path(&hir_path?)?;
         match resolution {
diff --git a/crates/ra_assists/src/handlers/fill_match_arms.rs b/crates/ra_assists/src/handlers/fill_match_arms.rs
index cc303285b..569efb768 100644
--- a/crates/ra_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ra_assists/src/handlers/fill_match_arms.rs
@@ -136,8 +136,20 @@ fn is_variant_missing(existing_arms: &mut Vec<MatchArm>, var: &Pat) -> bool {
 }
 
 fn does_pat_match_variant(pat: &Pat, var: &Pat) -> bool {
-    let pat_head = pat.syntax().first_child().map(|node| node.text());
-    let var_head = var.syntax().first_child().map(|node| node.text());
+    let first_node_text = |pat: &Pat| pat.syntax().first_child().map(|node| node.text());
+
+    let pat_head = match pat {
+        Pat::BindPat(bind_pat) => {
+            if let Some(p) = bind_pat.pat() {
+                first_node_text(&p)
+            } else {
+                return false;
+            }
+        }
+        pat => first_node_text(pat),
+    };
+
+    let var_head = first_node_text(var);
 
     pat_head == var_head
 }
@@ -351,6 +363,40 @@ mod tests {
     }
 
     #[test]
+    fn partial_fill_bind_pat() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A {
+                As,
+                Bs,
+                Cs(Option<i32>),
+            }
+            fn main() {
+                match A::As<|> {
+                    A::As(_) => {}
+                    a @ A::Bs(_) => {}
+                }
+            }
+            "#,
+            r#"
+            enum A {
+                As,
+                Bs,
+                Cs(Option<i32>),
+            }
+            fn main() {
+                match A::As {
+                    A::As(_) => {}
+                    a @ A::Bs(_) => {}
+                    $0A::Cs(_) => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
     fn fill_match_arms_empty_body() {
         check_assist(
             fill_match_arms,
diff --git a/crates/ra_hir_def/src/path.rs b/crates/ra_hir_def/src/path.rs
index ba16442bd..190d6d98d 100644
--- a/crates/ra_hir_def/src/path.rs
+++ b/crates/ra_hir_def/src/path.rs
@@ -154,7 +154,7 @@ pub enum GenericArg {
 
 impl Path {
     /// Converts an `ast::Path` to `Path`. Works with use trees.
-    /// DEPRECATED: It does not handle `$crate` from macro call.
+    #[deprecated = "Doesn't handle hygiene, don't add new calls, remove old ones"]
     pub fn from_ast(path: ast::Path) -> Option<Path> {
         lower::lower_path(path, &Hygiene::new_unhygienic())
     }
diff --git a/crates/ra_hir_ty/src/_match.rs b/crates/ra_hir_ty/src/_match.rs
index 3e6e1e333..fff257193 100644
--- a/crates/ra_hir_ty/src/_match.rs
+++ b/crates/ra_hir_ty/src/_match.rs
@@ -8,11 +8,11 @@
 //! This file includes the logic for exhaustiveness and usefulness checking for
 //! pattern-matching. Specifically, given a list of patterns for a type, we can
 //! tell whether:
-//! (a) the patterns cover every possible constructor for the type [exhaustiveness]
-//! (b) each pattern is necessary [usefulness]
+//! - (a) the patterns cover every possible constructor for the type (exhaustiveness).
+//! - (b) each pattern is necessary (usefulness).
 //!
-//! The algorithm implemented here is a modified version of the one described in:
-//! http://moscova.inria.fr/~maranget/papers/warn/index.html
+//! The algorithm implemented here is a modified version of the one described in
+//! <http://moscova.inria.fr/~maranget/papers/warn/index.html>.
 //! However, to save future implementors from reading the original paper, we
 //! summarise the algorithm here to hopefully save time and be a little clearer
 //! (without being so rigorous).
@@ -37,20 +37,26 @@
 //! new pattern `p`.
 //!
 //! For example, say we have the following:
+//!
+//! ```ignore
+//! // x: (Option<bool>, Result<()>)
+//! match x {
+//!     (Some(true), _) => {}
+//!     (None, Err(())) => {}
+//!     (None, Err(_)) => {}
+//! }
 //! ```
-//!     // x: (Option<bool>, Result<()>)
-//!     match x {
-//!         (Some(true), _) => {}
-//!         (None, Err(())) => {}
-//!         (None, Err(_)) => {}
-//!     }
-//! ```
+//!
 //! Here, the matrix `P` starts as:
+//!
+//! ```text
 //! [
 //!     [(Some(true), _)],
 //!     [(None, Err(()))],
 //!     [(None, Err(_))],
 //! ]
+//! ```
+//!
 //! We can tell it's not exhaustive, because `U(P, _)` is true (we're not covering
 //! `[(Some(false), _)]`, for instance). In addition, row 3 is not useful, because
 //! all the values it covers are already covered by row 2.
@@ -60,53 +66,61 @@
 //! To match the paper, the top of the stack is at the beginning / on the left.
 //!
 //! There are two important operations on pattern-stacks necessary to understand the algorithm:
-//!     1. We can pop a given constructor off the top of a stack. This operation is called
-//!        `specialize`, and is denoted `S(c, p)` where `c` is a constructor (like `Some` or
-//!        `None`) and `p` a pattern-stack.
-//!        If the pattern on top of the stack can cover `c`, this removes the constructor and
-//!        pushes its arguments onto the stack. It also expands OR-patterns into distinct patterns.
-//!        Otherwise the pattern-stack is discarded.
-//!        This essentially filters those pattern-stacks whose top covers the constructor `c` and
-//!        discards the others.
 //!
-//!        For example, the first pattern above initially gives a stack `[(Some(true), _)]`. If we
-//!        pop the tuple constructor, we are left with `[Some(true), _]`, and if we then pop the
-//!        `Some` constructor we get `[true, _]`. If we had popped `None` instead, we would get
-//!        nothing back.
+//! 1. We can pop a given constructor off the top of a stack. This operation is called
+//!    `specialize`, and is denoted `S(c, p)` where `c` is a constructor (like `Some` or
+//!    `None`) and `p` a pattern-stack.
+//!    If the pattern on top of the stack can cover `c`, this removes the constructor and
+//!    pushes its arguments onto the stack. It also expands OR-patterns into distinct patterns.
+//!    Otherwise the pattern-stack is discarded.
+//!    This essentially filters those pattern-stacks whose top covers the constructor `c` and
+//!    discards the others.
+//!
+//!    For example, the first pattern above initially gives a stack `[(Some(true), _)]`. If we
+//!    pop the tuple constructor, we are left with `[Some(true), _]`, and if we then pop the
+//!    `Some` constructor we get `[true, _]`. If we had popped `None` instead, we would get
+//!    nothing back.
+//!
+//!    This returns zero or more new pattern-stacks, as follows. We look at the pattern `p_1`
+//!    on top of the stack, and we have four cases:
+//!
+//!    * 1.1. `p_1 = c(r_1, .., r_a)`, i.e. the top of the stack has constructor `c`. We push onto
+//!           the stack the arguments of this constructor, and return the result:
+//!
+//!          r_1, .., r_a, p_2, .., p_n
+//!
+//!    * 1.2. `p_1 = c'(r_1, .., r_a')` where `c ≠ c'`. We discard the current stack and return
+//!           nothing.
+//!    * 1.3. `p_1 = _`. We push onto the stack as many wildcards as the constructor `c` has
+//!           arguments (its arity), and return the resulting stack:
 //!
-//!        This returns zero or more new pattern-stacks, as follows. We look at the pattern `p_1`
-//!        on top of the stack, and we have four cases:
-//!             1.1. `p_1 = c(r_1, .., r_a)`, i.e. the top of the stack has constructor `c`. We
-//!                  push onto the stack the arguments of this constructor, and return the result:
-//!                     r_1, .., r_a, p_2, .., p_n
-//!             1.2. `p_1 = c'(r_1, .., r_a')` where `c ≠ c'`. We discard the current stack and
-//!                  return nothing.
-//!             1.3. `p_1 = _`. We push onto the stack as many wildcards as the constructor `c` has
-//!                  arguments (its arity), and return the resulting stack:
-//!                     _, .., _, p_2, .., p_n
-//!             1.4. `p_1 = r_1 | r_2`. We expand the OR-pattern and then recurse on each resulting
-//!                  stack:
-//!                     S(c, (r_1, p_2, .., p_n))
-//!                     S(c, (r_2, p_2, .., p_n))
+//!          _, .., _, p_2, .., p_n
 //!
-//!     2. We can pop a wildcard off the top of the stack. This is called `D(p)`, where `p` is
-//!        a pattern-stack.
-//!        This is used when we know there are missing constructor cases, but there might be
-//!        existing wildcard patterns, so to check the usefulness of the matrix, we have to check
-//!        all its *other* components.
+//!    * 1.4. `p_1 = r_1 | r_2`. We expand the OR-pattern and then recurse on each resulting stack:
 //!
-//!        It is computed as follows. We look at the pattern `p_1` on top of the stack,
-//!        and we have three cases:
-//!             1.1. `p_1 = c(r_1, .., r_a)`. We discard the current stack and return nothing.
-//!             1.2. `p_1 = _`. We return the rest of the stack:
-//!                     p_2, .., p_n
-//!             1.3. `p_1 = r_1 | r_2`. We expand the OR-pattern and then recurse on each resulting
-//!               stack.
-//!                     D((r_1, p_2, .., p_n))
-//!                     D((r_2, p_2, .., p_n))
+//!          S(c, (r_1, p_2, .., p_n))
+//!          S(c, (r_2, p_2, .., p_n))
 //!
-//!     Note that the OR-patterns are not always used directly in Rust, but are used to derive the
-//!     exhaustive integer matching rules, so they're written here for posterity.
+//! 2. We can pop a wildcard off the top of the stack. This is called `D(p)`, where `p` is
+//!    a pattern-stack.
+//!    This is used when we know there are missing constructor cases, but there might be
+//!    existing wildcard patterns, so to check the usefulness of the matrix, we have to check
+//!    all its *other* components.
+//!
+//!    It is computed as follows. We look at the pattern `p_1` on top of the stack,
+//!    and we have three cases:
+//!    * 1.1. `p_1 = c(r_1, .., r_a)`. We discard the current stack and return nothing.
+//!    * 1.2. `p_1 = _`. We return the rest of the stack:
+//!
+//!          p_2, .., p_n
+//!
+//!    * 1.3. `p_1 = r_1 | r_2`. We expand the OR-pattern and then recurse on each resulting stack:
+//!
+//!          D((r_1, p_2, .., p_n))
+//!          D((r_2, p_2, .., p_n))
+//!
+//!    Note that the OR-patterns are not always used directly in Rust, but are used to derive the
+//!    exhaustive integer matching rules, so they're written here for posterity.
 //!
 //! Both those operations extend straightforwardly to a list or pattern-stacks, i.e. a matrix, by
 //! working row-by-row. Popping a constructor ends up keeping only the matrix rows that start with
@@ -120,73 +134,88 @@
 //! operates principally on the first component of the matrix and new pattern-stack `p`.
 //! This algorithm is realised in the `is_useful` function.
 //!
-//! Base case. (`n = 0`, i.e., an empty tuple pattern)
-//!     - If `P` already contains an empty pattern (i.e., if the number of patterns `m > 0`),
-//!       then `U(P, p)` is false.
-//!     - Otherwise, `P` must be empty, so `U(P, p)` is true.
+//! Base case (`n = 0`, i.e., an empty tuple pattern):
+//! - If `P` already contains an empty pattern (i.e., if the number of patterns `m > 0`), then
+//!   `U(P, p)` is false.
+//! - Otherwise, `P` must be empty, so `U(P, p)` is true.
+//!
+//! Inductive step (`n > 0`, i.e., whether there's at least one column [which may then be expanded
+//! into further columns later]). We're going to match on the top of the new pattern-stack, `p_1`:
+//!
+//! - If `p_1 == c(r_1, .., r_a)`, i.e. we have a constructor pattern.
+//!   Then, the usefulness of `p_1` can be reduced to whether it is useful when
+//!   we ignore all the patterns in the first column of `P` that involve other constructors.
+//!   This is where `S(c, P)` comes in:
+//!
+//!   ```text
+//!   U(P, p) := U(S(c, P), S(c, p))
+//!   ```
+//!
+//!   This special case is handled in `is_useful_specialized`.
+//!
+//!   For example, if `P` is:
+//!
+//!   ```text
+//!   [
+//!       [Some(true), _],
+//!       [None, 0],
+//!   ]
+//!   ```
 //!
-//! Inductive step. (`n > 0`, i.e., whether there's at least one column
-//!                  [which may then be expanded into further columns later])
-//!     We're going to match on the top of the new pattern-stack, `p_1`.
-//!         - If `p_1 == c(r_1, .., r_a)`, i.e. we have a constructor pattern.
-//!           Then, the usefulness of `p_1` can be reduced to whether it is useful when
-//!           we ignore all the patterns in the first column of `P` that involve other constructors.
-//!           This is where `S(c, P)` comes in:
-//!           `U(P, p) := U(S(c, P), S(c, p))`
-//!           This special case is handled in `is_useful_specialized`.
+//!   and `p` is `[Some(false), 0]`, then we don't care about row 2 since we know `p` only
+//!   matches values that row 2 doesn't. For row 1 however, we need to dig into the
+//!   arguments of `Some` to know whether some new value is covered. So we compute
+//!   `U([[true, _]], [false, 0])`.
 //!
-//!           For example, if `P` is:
-//!           [
-//!               [Some(true), _],
-//!               [None, 0],
-//!           ]
-//!           and `p` is [Some(false), 0], then we don't care about row 2 since we know `p` only
-//!           matches values that row 2 doesn't. For row 1 however, we need to dig into the
-//!           arguments of `Some` to know whether some new value is covered. So we compute
-//!           `U([[true, _]], [false, 0])`.
+//! - If `p_1 == _`, then we look at the list of constructors that appear in the first component of
+//!   the rows of `P`:
+//!     - If there are some constructors that aren't present, then we might think that the
+//!       wildcard `_` is useful, since it covers those constructors that weren't covered
+//!       before.
+//!       That's almost correct, but only works if there were no wildcards in those first
+//!       components. So we need to check that `p` is useful with respect to the rows that
+//!       start with a wildcard, if there are any. This is where `D` comes in:
+//!       `U(P, p) := U(D(P), D(p))`
 //!
-//!         - If `p_1 == _`, then we look at the list of constructors that appear in the first
-//!               component of the rows of `P`:
-//!             + If there are some constructors that aren't present, then we might think that the
-//!               wildcard `_` is useful, since it covers those constructors that weren't covered
-//!               before.
-//!               That's almost correct, but only works if there were no wildcards in those first
-//!               components. So we need to check that `p` is useful with respect to the rows that
-//!               start with a wildcard, if there are any. This is where `D` comes in:
-//!               `U(P, p) := U(D(P), D(p))`
+//!       For example, if `P` is:
+//!       ```text
+//!       [
+//!           [_, true, _],
+//!           [None, false, 1],
+//!       ]
+//!       ```
+//!       and `p` is `[_, false, _]`, the `Some` constructor doesn't appear in `P`. So if we
+//!       only had row 2, we'd know that `p` is useful. However row 1 starts with a
+//!       wildcard, so we need to check whether `U([[true, _]], [false, 1])`.
 //!
-//!               For example, if `P` is:
-//!               [
-//!                   [_, true, _],
-//!                   [None, false, 1],
-//!               ]
-//!               and `p` is [_, false, _], the `Some` constructor doesn't appear in `P`. So if we
-//!               only had row 2, we'd know that `p` is useful. However row 1 starts with a
-//!               wildcard, so we need to check whether `U([[true, _]], [false, 1])`.
+//!     - Otherwise, all possible constructors (for the relevant type) are present. In this
+//!       case we must check whether the wildcard pattern covers any unmatched value. For
+//!       that, we can think of the `_` pattern as a big OR-pattern that covers all
+//!       possible constructors. For `Option`, that would mean `_ = None | Some(_)` for
+//!       example. The wildcard pattern is useful in this case if it is useful when
+//!       specialized to one of the possible constructors. So we compute:
+//!       `U(P, p) := ∃(k ϵ constructors) U(S(k, P), S(k, p))`
 //!
-//!             + Otherwise, all possible constructors (for the relevant type) are present. In this
-//!               case we must check whether the wildcard pattern covers any unmatched value. For
-//!               that, we can think of the `_` pattern as a big OR-pattern that covers all
-//!               possible constructors. For `Option`, that would mean `_ = None | Some(_)` for
-//!               example. The wildcard pattern is useful in this case if it is useful when
-//!               specialized to one of the possible constructors. So we compute:
-//!               `U(P, p) := ∃(k ϵ constructors) U(S(k, P), S(k, p))`
+//!       For example, if `P` is:
+//!       ```text
+//!       [
+//!           [Some(true), _],
+//!           [None, false],
+//!       ]
+//!       ```
+//!       and `p` is `[_, false]`, both `None` and `Some` constructors appear in the first
+//!       components of `P`. We will therefore try popping both constructors in turn: we
+//!       compute `U([[true, _]], [_, false])` for the `Some` constructor, and `U([[false]],
+//!       [false])` for the `None` constructor. The first case returns true, so we know that
+//!       `p` is useful for `P`. Indeed, it matches `[Some(false), _]` that wasn't matched
+//!       before.
 //!
-//!               For example, if `P` is:
-//!               [
-//!                   [Some(true), _],
-//!                   [None, false],
-//!               ]
-//!               and `p` is [_, false], both `None` and `Some` constructors appear in the first
-//!               components of `P`. We will therefore try popping both constructors in turn: we
-//!               compute U([[true, _]], [_, false]) for the `Some` constructor, and U([[false]],
-//!               [false]) for the `None` constructor. The first case returns true, so we know that
-//!               `p` is useful for `P`. Indeed, it matches `[Some(false), _]` that wasn't matched
-//!               before.
+//! - If `p_1 == r_1 | r_2`, then the usefulness depends on each `r_i` separately:
 //!
-//!         - If `p_1 == r_1 | r_2`, then the usefulness depends on each `r_i` separately:
-//!           `U(P, p) := U(P, (r_1, p_2, .., p_n))
-//!                    || U(P, (r_2, p_2, .., p_n))`
+//!   ```text
+//!   U(P, p) := U(P, (r_1, p_2, .., p_n))
+//!            || U(P, (r_2, p_2, .., p_n))
+//!   ```
 use std::sync::Arc;
 
 use smallvec::{smallvec, SmallVec};
diff --git a/crates/ra_ide/src/completion/completion_context.rs b/crates/ra_ide/src/completion/completion_context.rs
index 9f4c582d0..560fb19e6 100644
--- a/crates/ra_ide/src/completion/completion_context.rs
+++ b/crates/ra_ide/src/completion/completion_context.rs
@@ -381,6 +381,7 @@ impl<'a> CompletionContext<'a> {
             self.is_path_type = path.syntax().parent().and_then(ast::PathType::cast).is_some();
             self.has_type_args = segment.type_arg_list().is_some();
 
+            #[allow(deprecated)]
             if let Some(path) = hir::Path::from_ast(path.clone()) {
                 if let Some(path_prefix) = path.qualifier() {
                     self.path_prefix = Some(path_prefix);
diff --git a/crates/ra_ide/src/snapshots/highlighting.html b/crates/ra_ide/src/snapshots/highlighting.html
index 33548d43c..5c2ff6ab5 100644
--- a/crates/ra_ide/src/snapshots/highlighting.html
+++ b/crates/ra_ide/src/snapshots/highlighting.html
@@ -62,6 +62,12 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     }
 }
 
+<span class="macro">macro_rules!</span> <span class="macro declaration">noop</span> {
+    ($expr:expr) =&gt; {
+        $expr
+    }
+}
+
 <span class="comment">// comment</span>
 <span class="keyword">fn</span> <span class="function declaration">main</span>() {
     <span class="macro">println!</span>(<span class="string_literal">"Hello, {}!"</span>, <span class="numeric_literal">92</span>);
@@ -80,6 +86,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
         <span class="comment">// Do nothing</span>
     }
 
+    <span class="macro">noop!</span>(<span class="macro">noop</span><span class="macro">!</span>(<span class="numeric_literal">1</span>));
+
     <span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable declaration mutable">x</span> = <span class="numeric_literal">42</span>;
     <span class="keyword">let</span> <span class="variable declaration mutable">y</span> = &<span class="keyword">mut</span> <span class="variable mutable">x</span>;
     <span class="keyword">let</span> <span class="variable declaration">z</span> = &<span class="variable mutable">y</span>;
diff --git a/crates/ra_ide/src/syntax_highlighting.rs b/crates/ra_ide/src/syntax_highlighting.rs
index ab45c364a..bbcd52a1c 100644
--- a/crates/ra_ide/src/syntax_highlighting.rs
+++ b/crates/ra_ide/src/syntax_highlighting.rs
@@ -160,23 +160,25 @@ pub(crate) fn highlight(
             // Check if macro takes a format string and remember it for highlighting later.
             // The macros that accept a format string expand to a compiler builtin macros
             // `format_args` and `format_args_nl`.
-            if let Some(fmt_macro_call) = parent.parent().and_then(ast::MacroCall::cast) {
-                if let Some(name) =
-                    fmt_macro_call.path().and_then(|p| p.segment()).and_then(|s| s.name_ref())
-                {
-                    match name.text().as_str() {
-                        "format_args" | "format_args_nl" => {
-                            format_string = parent
-                                .children_with_tokens()
-                                .filter(|t| t.kind() != WHITESPACE)
-                                .nth(1)
-                                .filter(|e| {
-                                    ast::String::can_cast(e.kind())
-                                        || ast::RawString::can_cast(e.kind())
-                                })
-                        }
-                        _ => {}
+            if let Some(name) = parent
+                .parent()
+                .and_then(ast::MacroCall::cast)
+                .and_then(|mc| mc.path())
+                .and_then(|p| p.segment())
+                .and_then(|s| s.name_ref())
+            {
+                match name.text().as_str() {
+                    "format_args" | "format_args_nl" => {
+                        format_string = parent
+                            .children_with_tokens()
+                            .filter(|t| t.kind() != WHITESPACE)
+                            .nth(1)
+                            .filter(|e| {
+                                ast::String::can_cast(e.kind())
+                                    || ast::RawString::can_cast(e.kind())
+                            })
                     }
+                    _ => {}
                 }
             }
 
@@ -493,6 +495,9 @@ fn highlight_element(
             h |= HighlightModifier::Unsafe;
             h
         }
+        T![!] if element.parent().and_then(ast::MacroCall::cast).is_some() => {
+            Highlight::new(HighlightTag::Macro)
+        }
 
         k if k.is_keyword() => {
             let h = Highlight::new(HighlightTag::Keyword);
diff --git a/crates/ra_ide/src/syntax_highlighting/tests.rs b/crates/ra_ide/src/syntax_highlighting/tests.rs
index 949bf59a0..070b24f45 100644
--- a/crates/ra_ide/src/syntax_highlighting/tests.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tests.rs
@@ -43,6 +43,12 @@ def_fn! {
     }
 }
 
+macro_rules! noop {
+    ($expr:expr) => {
+        $expr
+    }
+}
+
 // comment
 fn main() {
     println!("Hello, {}!", 92);
@@ -61,6 +67,8 @@ fn main() {
         // Do nothing
     }
 
+    noop!(noop!(1));
+
     let mut x = 42;
     let y = &mut x;
     let z = &y;
diff --git a/crates/ra_parser/src/grammar/expressions.rs b/crates/ra_parser/src/grammar/expressions.rs
index d6e8df32a..6e72eea66 100644
--- a/crates/ra_parser/src/grammar/expressions.rs
+++ b/crates/ra_parser/src/grammar/expressions.rs
@@ -50,10 +50,8 @@ fn expr_no_struct(p: &mut Parser) {
 }
 
 fn is_expr_stmt_attr_allowed(kind: SyntaxKind) -> bool {
-    match kind {
-        BIN_EXPR | RANGE_EXPR | IF_EXPR => false,
-        _ => true,
-    }
+    let forbid = matches!(kind, BIN_EXPR | RANGE_EXPR);
+    !forbid
 }
 
 pub(super) fn stmt(p: &mut Parser, with_semi: StmtWithSemi) {
diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index cb0e27dce..9541362f5 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -29,13 +29,7 @@ pub enum ProjectWorkspace {
     /// Project workspace was discovered by running `cargo metadata` and `rustc --print sysroot`.
     Cargo { cargo: CargoWorkspace, sysroot: Sysroot },
     /// Project workspace was manually specified using a `rust-project.json` file.
-    Json { project: JsonProject },
-}
-
-impl From<JsonProject> for ProjectWorkspace {
-    fn from(project: JsonProject) -> ProjectWorkspace {
-        ProjectWorkspace::Json { project }
-    }
+    Json { project: JsonProject, project_location: PathBuf },
 }
 
 /// `PackageRoot` describes a package root folder.
@@ -164,10 +158,15 @@ impl ProjectWorkspace {
                     format!("Failed to open json file {}", project_json.display())
                 })?;
                 let reader = BufReader::new(file);
+                let project_location = match project_json.parent() {
+                    Some(parent) => PathBuf::from(parent),
+                    None => PathBuf::new(),
+                };
                 ProjectWorkspace::Json {
                     project: from_reader(reader).with_context(|| {
                         format!("Failed to deserialize json file {}", project_json.display())
                     })?,
+                    project_location: project_location,
                 }
             }
             ProjectManifest::CargoToml(cargo_toml) => {
@@ -200,9 +199,11 @@ impl ProjectWorkspace {
     /// the root is a member of the current workspace
     pub fn to_roots(&self) -> Vec<PackageRoot> {
         match self {
-            ProjectWorkspace::Json { project } => {
-                project.roots.iter().map(|r| PackageRoot::new_member(r.path.clone())).collect()
-            }
+            ProjectWorkspace::Json { project, project_location } => project
+                .roots
+                .iter()
+                .map(|r| PackageRoot::new_member(project_location.join(&r.path)))
+                .collect(),
             ProjectWorkspace::Cargo { cargo, sysroot } => cargo
                 .packages()
                 .map(|pkg| PackageRoot {
@@ -219,7 +220,7 @@ impl ProjectWorkspace {
 
     pub fn proc_macro_dylib_paths(&self) -> Vec<PathBuf> {
         match self {
-            ProjectWorkspace::Json { project } => project
+            ProjectWorkspace::Json { project, .. } => project
                 .crates
                 .iter()
                 .filter_map(|krate| krate.proc_macro_dylib_path.as_ref())
@@ -235,7 +236,7 @@ impl ProjectWorkspace {
 
     pub fn n_packages(&self) -> usize {
         match self {
-            ProjectWorkspace::Json { project } => project.crates.len(),
+            ProjectWorkspace::Json { project, .. } => project.crates.len(),
             ProjectWorkspace::Cargo { cargo, sysroot } => {
                 cargo.packages().len() + sysroot.crates().len()
             }
@@ -251,13 +252,14 @@ impl ProjectWorkspace {
     ) -> CrateGraph {
         let mut crate_graph = CrateGraph::default();
         match self {
-            ProjectWorkspace::Json { project } => {
+            ProjectWorkspace::Json { project, project_location } => {
                 let crates: FxHashMap<_, _> = project
                     .crates
                     .iter()
                     .enumerate()
                     .filter_map(|(seq_index, krate)| {
-                        let file_id = load(&krate.root_module)?;
+                        let file_path = project_location.join(&krate.root_module);
+                        let file_id = load(&file_path)?;
                         let edition = match krate.edition {
                             json_project::Edition::Edition2015 => Edition::Edition2015,
                             json_project::Edition::Edition2018 => Edition::Edition2018,
@@ -540,7 +542,7 @@ impl ProjectWorkspace {
             ProjectWorkspace::Cargo { cargo, .. } => {
                 Some(cargo.workspace_root()).filter(|root| path.starts_with(root))
             }
-            ProjectWorkspace::Json { project: JsonProject { roots, .. } } => roots
+            ProjectWorkspace::Json { project: JsonProject { roots, .. }, .. } => roots
                 .iter()
                 .find(|root| path.starts_with(&root.path))
                 .map(|root| root.path.as_ref()),
diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index 61e686da5..a33a35cc1 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -51,7 +51,8 @@ pub use crate::{
     ptr::{AstPtr, SyntaxNodePtr},
     syntax_error::SyntaxError,
     syntax_node::{
-        Direction, NodeOrToken, SyntaxElement, SyntaxNode, SyntaxToken, SyntaxTreeBuilder,
+        Direction, NodeOrToken, SyntaxElement, SyntaxElementChildren, SyntaxNode,
+        SyntaxNodeChildren, SyntaxToken, SyntaxTreeBuilder,
     },
 };
 pub use ra_parser::{SyntaxKind, T};
diff --git a/crates/ra_syntax/test_data/parser/inline/err/0009_attr_on_expr_not_allowed.rast b/crates/ra_syntax/test_data/parser/inline/err/0009_attr_on_expr_not_allowed.rast
index 0656fdf73..4e3fa704e 100644
--- a/crates/ra_syntax/test_data/parser/inline/err/0009_attr_on_expr_not_allowed.rast
+++ b/crates/ra_syntax/test_data/parser/inline/err/0009_attr_on_expr_not_allowed.rast
@@ -56,4 +56,3 @@ [email protected]
       [email protected] "}"
   [email protected] "\n"
 error 24..24: attributes are not allowed on BIN_EXPR
-error 44..44: attributes are not allowed on IF_EXPR
diff --git a/crates/rust-analyzer/src/bin/main.rs b/crates/rust-analyzer/src/bin/main.rs
index 8d071ab1c..99e3f7173 100644
--- a/crates/rust-analyzer/src/bin/main.rs
+++ b/crates/rust-analyzer/src/bin/main.rs
@@ -108,11 +108,11 @@ fn run_server() -> Result<()> {
             config.update(value);
         }
         config.update_caps(&initialize_params.capabilities);
+        let cwd = std::env::current_dir()?;
+        config.root_path =
+            initialize_params.root_uri.and_then(|it| it.to_file_path().ok()).unwrap_or(cwd);
 
         if config.linked_projects.is_empty() {
-            let cwd = std::env::current_dir()?;
-            let root =
-                initialize_params.root_uri.and_then(|it| it.to_file_path().ok()).unwrap_or(cwd);
             let workspace_roots = initialize_params
                 .workspace_folders
                 .map(|workspaces| {
@@ -122,7 +122,7 @@ fn run_server() -> Result<()> {
                         .collect::<Vec<_>>()
                 })
                 .filter(|workspaces| !workspaces.is_empty())
-                .unwrap_or_else(|| vec![root]);
+                .unwrap_or_else(|| vec![config.root_path.clone()]);
 
             config.linked_projects = ProjectManifest::discover_all(&workspace_roots)
                 .into_iter()
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 1253db836..0e7a937a0 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -38,12 +38,13 @@ pub struct Config {
 
     pub with_sysroot: bool,
     pub linked_projects: Vec<LinkedProject>,
+    pub root_path: PathBuf,
 }
 
 #[derive(Debug, Clone)]
 pub enum LinkedProject {
     ProjectManifest(ProjectManifest),
-    JsonProject(JsonProject),
+    InlineJsonProject(JsonProject),
 }
 
 impl From<ProjectManifest> for LinkedProject {
@@ -54,7 +55,7 @@ impl From<ProjectManifest> for LinkedProject {
 
 impl From<JsonProject> for LinkedProject {
     fn from(v: JsonProject) -> Self {
-        LinkedProject::JsonProject(v)
+        LinkedProject::InlineJsonProject(v)
     }
 }
 
@@ -167,6 +168,7 @@ impl Default for Config {
             lens: LensConfig::default(),
             hover: HoverConfig::default(),
             linked_projects: Vec::new(),
+            root_path: PathBuf::new(),
         }
     }
 }
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 8ec571b70..cc9bb1726 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -121,7 +121,12 @@ pub fn main_loop(config: Config, connection: Connection) -> Result<()> {
                         })
                         .ok()
                     }
-                    LinkedProject::JsonProject(it) => Some(it.clone().into()),
+                    LinkedProject::InlineJsonProject(it) => {
+                        Some(ra_project_model::ProjectWorkspace::Json {
+                            project: it.clone(),
+                            project_location: config.root_path.clone(),
+                        })
+                    }
                 })
                 .collect::<Vec<_>>()
         };
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index 2141bfc20..981565cd7 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -10,17 +10,17 @@
 pub mod mark;
 
 use std::{
-    fs,
+    env, fs,
     path::{Path, PathBuf},
 };
 
-pub use ra_cfg::CfgOptions;
+use serde_json::Value;
 use stdx::split1;
+use text_size::{TextRange, TextSize};
 
+pub use ra_cfg::CfgOptions;
 pub use relative_path::{RelativePath, RelativePathBuf};
 pub use rustc_hash::FxHashMap;
-use serde_json::Value;
-use text_size::{TextRange, TextSize};
 
 pub use difference::Changeset as __Changeset;
 
@@ -625,8 +625,6 @@ pub fn skip_slow_tests() -> bool {
     should_skip
 }
 
-const REWRITE: bool = false;
-
 /// Asserts that `expected` and `actual` strings are equal. If they differ only
 /// in trailing or leading whitespace the test won't fail and
 /// the contents of `actual` will be written to the file located at `path`.
@@ -642,7 +640,7 @@ fn assert_equal_text(expected: &str, actual: &str, path: &Path) {
         fs::write(path, actual).unwrap();
         return;
     }
-    if REWRITE {
+    if env::var("UPDATE_EXPECTATIONS").is_ok() {
         println!("rewriting {}", pretty_path.display());
         fs::write(path, actual).unwrap();
         return;